Filament connection.



UNITED sTATEs PATENT oEEioE.

JOHN W. HOWELL, OF NEWARK, NEW JERSEY, .ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION 0F NEW YORK. Y

FILAMENT CONNECTION.

Specification. of Letters Patent.

Patented Apr. 9, 1912.

Application filed August 7, 1907. Serial No. 387,453.

To all whom it may concern.:

Be it known that I,'Joi1ivl WV. HOWELL, a citizen of the United States, residing at Newark, county of Essex, State of New Jersey, have invented certain new and useful Lamp filaments of refractoi'fy metal, suchl as tungsten, have heretofore been connected with leadingin conductors, say of nickelfby fusing the end of the nickel wire about the tungsten filament by means of anelectric arc operated in hydrogen. For certain reaj sons I niay desire that the oint or connection shall bev established without complete fusion of the end of the nickel or other leading-in wire, and my present invention comprises a method whereby a firm connection may he established without this fusion.

In the accompanying drawing-Figure 1 is av perspective view of a metal filament lamp embodying my invention; Fig. 2 is van en.

larged View of the joint between the leadingnconductor and filament before the joint is completed; Fig. 3 is a'view of the joint a modification in the method of forming the `oint. v J The incandescent lamp illustrated in Fig. 'l comprises a lamp stem 1 on which is mounted a glass pedestal 2 carrying refractory hooks 3 which engage with the refractory metal filament loops 4 of ,tungsten orY other suitable metal. These loops are supm plied withv current and are connected together at their ends by leading-in conductors 5 of nickel or platinum or other suitable metal or alloy.

To make a firm connection between the leading-in wires 5 and the metal filaments 4, I arrange the arts as shown in Fig. 21. A hook is made in the end of the leading-in conductor 5 and-the end of the filament 4 is placed in this hook; the point of Contact between the two is then pasted overmwith,

when complete; and Fig. 4 illustrates very finely divided tungsten er copperinixed with a little gum arabic. if next draw an arc from the end of the book by means of to run into the paste at the corner of the hook where it fuses withl the paste and also with the filament but leaves unfused a part of the paste above the joint. As the paste fuses with difficulty, it is very easy to fuse a part of the paste to the. tungsten andstiil leave the top part simply hardened or sintered together about the filament. This hardened or sintered part forms a protec-` tive body just above the joint and appears to protect the filament from the action which has heretofore caused filaments to break at this oint.

As a modi cation in the above described method I have used, with success, that illus tiated in Fig. 4i. In this case the hook of the leading-'iii wire is: Triade sui/aller than that illustrated in 2 and .the arc is ap; plied to the corner of the hook, as shown the drawing, and is of a strength insuiii cient to fuse the joint but sufficient to beat it to bright red heat lor even to white heat. The arc siiiters 'the paste strongly to the filament and to the leadi'ngm wire and makes avery hard joint between the two. The method, as described, is very easy and quick itt'nd is quite suited for commerciai applica ion.

The above described arc or sintering operation rnay be carried out in hydrogen or in other suitable protective atmosphere, as will be readily 'understood by persons skilied iii the art.

Y'Vhat I claim as new and desire te secure j by Letters latent of the United States,is,-

i. 7Ihe met.M i of eoiinecting tungsten filament to a conductor, which consist-s in pastingl the joint with copper paste than sintering the paste by. means of an are.

The method ef connecting a L nient to a. wire, which 'n pasting the joiiitand then heating "at by di ing an are from the wim to temperat high enough to sinter 'i enough to avoid complete i i 3. The method of connect filament to a conductor, w pasting the joint. ben heating the joint and regulating fl ttf? filament tered paste.

paste above the conductor is sintered while other portions are fused.

4. The method of joining atungsten ila-l, ment to a nickel Wire, which consists in pasting'the joint with finely divided metal held in a binder and heating said joint suiciently to harden the paste still leaving un? fused that'part which is above the wire. f

5. A connection between a tungsten lamp .ilament and its conductor, consisting of 17'. A connectionrbetween af metal lamp` filament 'and "a conductor, comprising a a'sted joint in which part'of the paste is used vand part only sintered.

8. 'A pasted. joint for metalflamp filaments having a sintered portionand a fusedportion.

9. The method 'of connecting a metal filament to avv/ire, which .consists in pasting ythe joint and then fusing a portion of said Wire While leaving unused'a part of said paste.

10. The method. of connecting a tungsten filament to 'a conductor, which" consists in pasting the joint with metal paste, and then electrically fusing a'portion- ,ofV said conductor and fusing a part onlyof said paste.

11. A-joint between a metal lamp iilament yand a conductor, part or'V which has been fused, havinga sintered portion and a fused portion. i 7

12. The method which consists in uniting by fusion afilament and an element which is to be secured thereto while the portion of the filament adjacent the point or' fusion is, protected by the application of suitable material.

13. rlhe method which consists in uniting by fusion a metal filament and an element which is to be secured thereto while the portion of the filament adjacent the point of fusion is protected by the application of reractory material.

14. The method of connecting a metal lilament and a conductor which consists in uniting them by fusion after applying suitable material to said filament to protect the portion of it adjacent the point of fusion from contamination. f

15. The method of connecting a metal filament and a conductor which consist-s in applying protective material to the iilament adjacent the conductorand then electrically fusing the latter to unite it with the filament, leaving unfused at least a portion of said protective material. l v

, 16. The method of connecting a metal filament to a conductor which consists in applying protective material to the filament adjacent the conductor and then uniting by fusion the conductor and the'end portion of the lament. i

17. A conductive joint between a refractory -metal filament and a metallic member which comprises a fused portion of said4 member and metal surroundingthe filament at the joint'adapted to prevent deteriora'- tion ofthe filament by the material of said member. l l j 18.v A conductive joint bet-Ween a refractory metal filament anda metallic member Which comprises a fused portion of said member alloyed with said filament nearl the end thereof and metal adjacent the operat-- ing portion of the filament adapted to pre-x vent deterioration of the portion of the ilament b v the metal of said member.

In Witness W'fhereof, I have hereunto set y my hand this 5th day of August, 1907.

Witnesses: A v v CHAs. H. HEELEY,

J. HARRY ELKINS.

Joint W; HOWELL.l j, 

